I have a shed/workshop that is too hot to use. I have a window AC, but
it's too big for the windows in the shed. I've decided to install it in
the wall. The walls are just studs with a plywood siding. It's just
rough studs inside, so it's just a matter of cutting thru the plywood
siding. The problem is how to seal it so rain and insects dont get in
around it. Even if I cut it fairly tight, there will still be a gap,
and water will come in during rains, and damage the wood. I suppose
several tubes of silicone caulk would work, but that would make it
impossible to remove for repairs.
What's the trick to this?
On Jul 6, 9:33 am, firstname.lastname@example.org wrote:
I had the same scenario a few years ago after I built my workshop. I
ended up cutting a hole in the siding just big enough for the A/C to
fit though it. I then trimmed it out with some 1x4's that matched the
corner boards of the workshop. I just caulked where the trim touched
the A/C and where the trim touched the siding. If it ever needs to be
removed, I'll just cut the caulking with a razor blade and remove the
trim. The inside has OSB covering the walls, so I just cut some
quarter inch thick slices of a 2x4 and used them towrap around the A/C
to seal it inside the shop.
Having the A/C definitely makes a difference in there during the
What Rob said, plus, make sure to mount the AC sloping downward on the
outside so that rain and internal condensation go out not into your
workshop If you can't cut an opening within 1/8 inch of the
dimensions of the AC, you shouldn't be building a workshop. One or two
tubes of caulking should be more than enough to fill the 1/8 inch
gap. Use backing materials such as a foam rubber strip to keep the
caulking frorm going into the hole without stopping.
re: "If you can't cut an opening within 1/8 inch of the dimensions of
the AC, you shouldn't be building a workshop"
He said he *has* a shed/workshop, not that he's building one.
Obviously, there's more to this than just cutting a hole and caulking
Without a window, there's no sill to rest the unit on. The unit can't
be (OK, shouldn't be) just balanced on the plywood.
A sill will be needed to rest the unit on and a header installed to
keep the unit from tipping backward. Obviously not a huge endeavor,
but certainly more than just cutting a hole in the wall.
Pick a shady spot where the AC can do it's business.
Cut a hole of the appropriate size ( maybe 1/8" larger than the AC unit).
Nail up 2X4s to frame the hole and attach to the studs. Don't caulk, use
sticky backed foam tape on the inside. This tape will need to be replaced
every 4-5 yrs. On the outside paint the siding to protect it from water and
surround the opening with molding to make it look snazzy.
put a bicycle inner tube around the air conditioner and a frame on
the outside about 1/2 inch bigger all around than the air conditioner.
Stich the tube into the gap between the unit and the frame and inflate
enough to give a tight seal.
On Jul 6, 11:33 am, email@example.com wrote:
One thing to make sure of is that the side vents are not blocked by
the wall or any trim that you install.
Wall mount units, especially ones that fit into a sleeve, have all of
the venting on the rear. Check your unit to be sure it can be mounted
in the wall without blocking the side vent.
I know it's an extra expense, but have you considered purchasing a new-
construction window from a home center and installing that first?
Better yet, if you have a house parts/renovation outlet anywhere
nearby, I'll bet you could get a used shop-grade window pretty darn
You'd have the added advantage of more light, ease of removing the AC
in the winter (if you have winter) and of course, no fussing around
with trying to make the unit work where it wasn't meant to.
On 7/6/2012 10:33 AM, firstname.lastname@example.org wrote:
Basically what they said, but I'd flash it as well--probably use a piece
of the adhesive flashing--before the finishing trim since it's intended
as a permanent installation. Essentially treat it as if were installing
a new window.
On Fri, 06 Jul 2012 10:33:47 -0500, email@example.com wrote:
Based on memory of my dad (carpenter) did many moons ago, I'd say what
you got for advice is valid. The only thing is make sure, if it's
important to you, to not allow the unit to be pushed back into the
workshop to prevent burglary. Not sure how to do this but I'm sure
someone else knows or Google around.
When I mounted one in my trailer vibration was a consideration. Mine
floats. PVC siding cut to form a curved water shed on top. Sides were
filled in with stick on black foam insulation tape. Just part of side vents
blocked, but covered inside section. Bottom on pads, and pushed down on
inside top. Too much slant will decrease efficiency if the splash wheel
does not get wet.
As someone has said, use backer rod to seal the gap around the air
conditioner and "window" framing.
Make your finished opening about 1/2" larger, on all sides, than your
air conditioner's housing. You'll need the extra space for possible
reinstallation modifications, later, if need be.
Depending on your unit, some older units will sweat (condensate) on
their sides and bottom, causing moisture to drip onto the window sill
and down the siding of the shop's exterior.... and maybe on the
interior, also. If this happens, reinstall with 1/4" spacers (rods)
between the air conditioner housing and sill. Insert sheet metal
(flashing) on the sill to prevent the condensation from wetting the
sill and other areas, there. Backer rod the lower interior gap
(where the spacers are), leaving the exterior's lower gap open for
The housing is supposed to help prevent condensation from forming,
this way, but with some older units, the insulation on the housing (if
originally there) will have become old, worn away and/or
disfunctional, hence the unit may condensate onto the wall's/window's
On Jul 6, 11:33 am, firstname.lastname@example.org wrote:
First off, your building is too hot to use because
it is just plywood and studs... Spend money on
adding some insulation, vapor barrier and an
interior wall surface... Otherwise your AC unit
will definitely need some repairs fairly soon
trying to keep up with the cooling load you
are saddling it with...
Secondly, you need a sleeve rated unit when
you are installing an AC unit through the wall...
The sleeve is installed to the properly built
wall structure and weatherproofed and the
compatible AC unit slides right in...
If you are so dead set on re-purposing the
specific AC unit you have available rather
than buying one properly suited to the
application, then buy and properly install
a window large enough to allow the AC
you have to be used in the manner it was
designed to be used...
A sleave type is only required for thicker walls. They are a lot
harder to find, and more expensive.
Just frame in a hole the size an open window would need to be to
install the window air conditioner, complete with sloped sill, and
install the air conditioner as if it was in a window. You MIGHT want
to put an extended flashing as a "drip guard" across the top to
redirect falling rain.
Insulating the shop - particualarly the roof - would definitely be a
good idea that will pay for itself quickly. DO NOT use beaded styrene
board insulation (styrofoam) and leave it uncovered.
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